applet1.java

keyBoard Event

/*源程序清单4-8*/

import java.awt.*;
import java.applet.*;
import java.util.*;

public class Applet1 extends Applet implements Runnable
{
    AudioClip audioClip;
    Thread ShapeThread = null;
    Random RandomNumber = new Random( );
    Color ImageColor;

    public void init( )
    {
       audioClip = getAudioClip(getCodeBase(),"Sample.AU");
    }
   
    public void start( )
     {
      if (ShapeThread==null)
        {
          ShapeThread= new Thread(this);
          ShapeThread.start();
        }
     }

    public void run()
     {
        while (true)
        {
           switch (RandomNumber.nextInt()%5){
            case 0:ImageColor = Color.black;
                   break;
            case 1:ImageColor = Color.blue;
                   break;
            case 2:ImageColor = Color.cyan;
                   break;
            case 3:ImageColor = Color.magenta;
                   break;
            case 4:ImageColor = Color.orange;
                   break;
            default:ImageColor = Color.red;
           }
         try
           {
            ShapeThread.sleep(300);
           }
         catch(InterruptedException e)
           {
            //忽略异常   
           }
         repaint();
           }
      }

      public void paint(Graphics g)
      {
          g.setColor(ImageColor);
          audioClip.play();
          switch(RandomNumber.nextInt()%2)
          {
            case 0:g.fillRect(25,25,200,200);
                   break;
            default:g.fillOval(25,25,200,200);
                   break;
          }
       }
   }